Jose Mourinho will demand Juan Mata personally tells him that he wants to join Manchester United before pushing the green light on a £40million switch to Old Trafford.

Chelsea are prepared to consider a £40m bid from United for Mata, but the Spaniard must make his wish clear to Mourinho in order to force through a permanent move away from Stamford Bridge.

The final decision on whether to sell Mata is being left to Mourinho and he will only act once the player has approached him.

Atletico Madrid want to take Mata on loan with an option to buy the 25-year-old at the end of the season. Sending the player back to Spain would be preferable to Mourinho, particularly if Chelsea can secure first option on striker Diego Costa in return.

Kevin De Bruyne was put in a similar position to Mata, when Mourinho made the Belgian tell him he wanted to join Wolfsburg on a permanent deal before finally agreeing to an £18m deal.

Chelsea had tried to push De Bruyne on loan to Atletico until the end of the season, before the 22-year-old and his agent met with Mourinho to state his desire to go to Wolfsburg permanently.

Despite relegating him behind Oscar and leaving him on the substitutes’ bench for long spells, Mourinho has claimed he does not want to sell Mata this month,

But, as in the case of De Bruyne, Mourinho is likely to reconsider that stance if the midfielder personally expresses a firm desire to leave and a big bid is accepted.

It is thought the prospect of joining United interests Mata, who has been clear that he will not be forced to move to a club he is unsure about or that simply suits Chelsea.

Mata’s father, Juan senior, acts as his agent and had been planning to try to secure a move to Barcelona for his son at the end of the season.

But United’s interest is likely to prompt a rethink, particularly with this summer’s World Cup fast approaching. Mata’s Spain team-mate Santi Cazorla said: “If Juan doesn’t play he will want to leave Chelsea, that’s obvious.”